Yet another post from me

We found one of the pups squashed under mum this afternoon. We have someone sitting with her all the time as she has been very nervous but didn't realise it had happened. It was only when my husband when to do a quick head count that he found her under mum and barely alive. We did manage to revive her and for the time being at least she seems to be fine again and feeding well. A couple of times today though mum has 'plonked' herself down completely trapping a little one underneath her and so we've had to quickly retrieve it.

We are going to make sure we stay with her constantly and take it in turns to watch overnight but I am still worried about her doing it again.

She's in a whelping box with the 'rails' around the sides but it's still happening. We have already lost two from the litter of 7 (one stillborn and the runt died in the night despite our very best efforts) and it's been heartbreaking. We are prepared to whatever it takes to make sure that the remaining pups are ok and that Mum is ok too.

Should we remove them from Mum and just bring them back for feeds?

As they still need to be suckling almost continuously to bring in the milk, taking them away would be counter-productive. As she's a clumsy new mum (surprisingly common) you need someone sitting with them 24/7 at least until their eyes are open. I find that's when they become more capable of getting away form mum's bulk when they need to.

The grandmother of my current pups was a clumsy Mum! Great apart from that but only ever let pups to one side at a time and would crash down.
The worst thing I think that ever happened to me was to find a 4 week old pup totally flattened  and of course had died. At 4 weeks we thought the danger had passed but you can never be sure while they are so vulnerable.
Others including her daughter have been totally careful and stepped around the pups and when they know a pup is behind sort of hold their back in so they do not totally lay flat.
Glad you were able to revive the pup as I was too late but at the age yours are for sure you need to carry on with the watchful eye you have been.

This is why sources state canine infant mortality is around 30%.

Unless supervised crushing deaths especially with less agile and heavier breeds are a definite risk.

I also once lost a pup to crushing in the middle of the box,  it had been a long labour and both she and I were shattered.  This was a normally very careful bitch with her second litter.

I would keep a careful eye on that puppy in case there are internal injuries not apparent at the moment.

Constant supervision - it's the only way.   Having lived with my Basset mums only, even if they are not actually lying down on the puppies being so low-slung, with the milk bar to add to that, it's always on the cards that this could happen.   We had pig rails and quite often it's the puppies who would take themselves under the 'shelf' this provides to sleep when not nursing, but fact is somebody had to be there pretty much 24/7 - much as once I had them all settled, I'd pop out of the room leaving the door adjar to hear.   Mine would make a ton of noise if they got stuck which prevented an actual squashing, but the possibility was always there.   And was the worst part of the first weeks which with a good mum, should have been the easy part!!

I'd not take the puppies away from her at this point.

This is the very reason I spend 3-4 weeks completely sleep deprived ! with a large breed like mine they are never ever left alone. I am 24/7 with them (Or DOH is ) If I need the loo I take Mum with me. Until they are up on thier feet and Mum is visiting less often it's a full time job. Its also the reason I employ my dog sitter to do the same job if I need to go to work. Thats why good dog breeders are in a constant state of puppy head for the first month or so !!! Mum needs 24 hour access to her babies so I am on 24 hour supervision. No other way.

And people think puppies expensive,  if you worked out the man hours on top of the expenses,  your average breed would cost a 4 figure sum.

Most breeds decently bred and reared are well under a thousand.